Support Ring Research Articles

Surgical Reconstruction of Mitral-Tricuspid Insufficiency Combined with Biatriomegaly in Marfan Syndrome

The aim. To analyze the results of introduction of complex reconstruction of the left and right parts of the heart in Marfan syndrome combined with mitral-tricuspid insufficiency, biatriomegaly and left ventriculomegaly.
 Materials and methods. As an example of this pathology, we present our observation. Female patient T., 24 years old, was examined and treated from 7/27/2022 to 8/17/2022 at the Department of Surgical Treatment of Acquired Heart Diseases of the National Amosov Institute of Cardiovascular Surgery of the National Academy of Medical Sciences of Ukraine with a diagnosis: Marfan syndrome. Stage IV mitral-tricuspid insufficiency. Biatriomegaly. High pulmonary hypertension. Permanent form of atrial fibrillation (for 10 years, since 2011). IIB heart failure with left ventriculomegaly with reduced left ventricular ejection fraction. NYHA functional class IV+. The patient underwent surgery in the following volume: mitral valve replacement with full preservation of the valve apparatus + tricuspid valve plasty with the imposition of a support ring + triangular plasty of the left atrium with its partial resection + resection of the right atrium.
 Results. Within 4 months after surgery, echocardiographic parameters showed significant decrease in the volume of the left ventricle, the diameters of both atria. In addition, there was a significant decrease in the level of N-terminal pro-brain natriuretic peptide and manifestations of heart failure.
 Conclusion. Taking into account the initial serious condition of the patient with Marfan syndrome and advanced mitral-tricuspid heart disease, left ventriculomegaly with a reduced left ventricular ejection fraction, biatriomegaly (left atrium 7.2 cm, right atrium 6.5 cm), permanent form of atrial fibrillation, complex reconstruction of the left and right parts of the heart leads to an improvement in the functional state of the myocardium.

Optimization of three-dimensional traveling wave drive for a PZT thin-film micro-motor based on stiffness tuning of the supporting structure

This paper is based on the analysis of the three-dimensional motion of the PZT (lead zirconate titanate) thin-film traveling wave micro-motor and presents an optimization study of the effect of the radial component on the output torque and maximum speed. Based on theoretical analysis, it is proposed that the inconsistency of the equivalent constraint stiffness of the inner and outer rings is the main factor in the radial component of the traveling wave drive. Considering the large computational and time costs of 3D (three-dimensional) transient simulation, the residual stress-relieved deformation state in a steady state is used to equivalently characterize the inner and outer ring constraint stiffness of the micro-motor, and then the outer ring support stiffness is adjusted to achieve the consistency of the inner and outer ring constraint stiffness and the optimization of the radial component reduction, as well as to improve the flatness of the micro-motor interface under residual stress and optimize the contact state between the stator and rotor. Finally, performance testing of the device prepared by the MEMS process showed that the output torque of the PZT traveling wave micro-motor increased by 21% (14.89 μN*m), the maximum speed increased by 18% (>12000 rpm), and the speed instability was optimally reduced by a factor of 3 (<10%).

Our experience with mitral valve repair using an autologous pericardium for recurrent mitral regurgitation

Objective: To present outcomes of mitral valve reinterventions for recurrent degenerative mitral regurgitation.Materials and methods: From May 2017 to February 2021 3 male patients aged 43, 50, and 54 years and an 18-year-old female patient underwent mitral valve reinterventions with an autopericardial strip at Scientific Research Institute – Specialized Cardiac Surgery Clinical Hospital named after Academician B.A. Korolev. Three patients had primary mitral valve annuloplasty using a support ring and 1 patient using an autopericardial strip. In this patient group recurrent mitral regurgitation developed within 6-33 months between the primary repair and reintervention (20 ± 13.5 months on average).Results: No hospital mortality was reported. Cardiopulmonary bypass duration averaged 109.8 ± 19.7 minutes, and myocardial ischemia lasted 77.5 ± 10.1 minutes. Two patients had an adjunctive repeat radiofrequency Maze procedure, with the supraventricular rhythm restored in 1 patient. Echocardiography demonstrated that mitral regurgitation did not exceed grade 1 at discharge. Reintervention using an autopericardial strip for recurrent mitral regurgitation significantly reduces sizes of the left atrium and left ventricle. Ejection fraction did not change after the intervention. Mitral valve peak gradient in all cases did not exceed 9 mm Hg.Conclusions: The key to a successful mitral valve reintervention is a qualitative analysis of the recurrence causes and use of various techniques and materials for intervention on the mitral valvular complex. Mitral valve reinterventions, especially in young patients, are justified if certain safety conditions are met and have similar outcomes to primary interventions.

МОДЕЛЮВАННЯ НАПРУЖЕНО-ДЕФОРМОВАНОГО СТАНУ ТОНКОСТІННИХ КУПОЛІВ З ПОЛІКАРБОНАТУ ДЛЯ РАЦІОНАЛЬНОГО ПРОЕКТУВАННЯ

The paper contains the further developed of method for calculating thin-walled dome systemswithout a stationary foundation. Have been carried out the detailed analysis of the fundamental design solutions for frameless collapsible spherical polycarbonate domes, which are used by modern world manufacturers of these structures. Have been done a brief description of the momentless theory of the operation of spherical shells, which is adapted for polycarbonate domes. Have been considered a simplified analytical model of the stress-strain state of a spherical shell with an equatorial diameter of up to5 m under the influence of climatic influences for the subsequent verification of detailed models. Have been developed highly detailed finite element models of domes of different sizes, taking into account technological openings and structural stiffeners (support ring and door frame) under the wind, snow, ice loads and under other climatic influences. Have been identified the fragments with the highest stresses from various loads and forms of the deformation of the structure.Have been considered separately the issues related to the loss of shape stability, position and balance of a thin-walled spherical shell, as a light temporary structure. Have been proven that the worst influence on the dome structures is the windinfluence, based on the stability criterion. Have been determined the estimated value of the aerodynamic lifting force from wind effects on the dome. Have been proven that the lifting force far exceeds the stabilizing force of the weight of a thin-walled dome. Have been revealed with the help of the performed calculations, it was that a frameless spherical polycarbonate dome inevitably БУДІВЕЛЬНІ КОНСТРУКЦІЇНАУКОВО-ТЕХНІЧНИЙ ЖУРНАЛ “СУЧАСНІ ТЕХНОЛОГІЇ, МАТЕРІАЛИ І КОНСТРУКЦІЇ В БУДІВНИЦТВІ”84loses its balance stability due to the action of wind loads and requires unfastening with anchors. Have been proposed a rational method for anchoring dome structures at temporary earthen construction sites using geo-screws or metal screw piles. Have been revealed the addiction between the radius of curvature of a spherical dome and the rational thickness of polycarbonate based on the criteria of stiffness and strength. Have been formulated the constructive recommendations regarding the rational design of polycarbonate dome systems. Have been developed the technological regulations for the further safe operation of domes, and have been outlined the directions for further scientific research on this topic

The effect of auxeticity on the vibration of conical sandwich shells with ring support under various boundary conditions

Auxetic materials, materials demonstrating negative Poisson's ratio, have revolutionized the use of materials in industries, as they demonstrate superb acoustic response, fracture resistance, and energy absorption. For the first time, this study embraces the free vibration of conical shells consisting of an auxetic core with and without ring support under various boundary conditions. First, the material characteristics of the auxetic core are calculated by means of a micromechanical approach. Afterwards, the kinematic motion equations of the conical shell are derived utilizing the first-order shear deformation theory. Finally, the governing equations are solved using the powerful generalized differential quadrature element method (GDQEM). The primary goal of this paper is to study the role of implementing an auxetic core as well as ring support in determining the vibrational behavior of the structure. The results of the study showed that the honeycomb interior angle and the presence of ring support can significantly affect the natural frequency of the structure. Lower frequencies can be reached as the interior angle increases. The importance of ring position is found to be highly dependent on the longitudinal mode shapes of vibration. The impact of ring position on natural frequencies is affected by the semi-vertex angle of the cone, and a shift in frequency peaks can be observed by increasing the semi-vertex angle.

Surgical Reconstruction of Mitral Restenosis Complicated by a Critically Small Left Ventricular Cavity and Giant Left and Right Atriomegaly (Clinical Case)

Background. Comprehensive reconstruction of the left and right parts of the heart in giant left atriomegaly, adequate tactics of mitral valve replacement in case of concomitant tricuspid insufficiency and dilation of the right atrium lead to an improvement in the functional state of the myocardium as early as at the hospital stage.&#x0D; Case description. Patient B., a 67-year-old woman, was examined and treated from July 12 to August 2, 2016 at the Department of Surgical Treatment of Acquired Heart Diseases of the National Amosov Institute of Cardiovascular Surgery of the National Academy of Medical Sciences of Ukraine with a diagnosis: stage IV mitral restenosis, condition after closed mitral commissurotomy in 2001, critically small cavity of the left ventricle, giant left atriomegaly, IV degree tricuspid insufficiency, right atriomegaly, high pulmonary hypertension, permanent form of atrial fibrillation for 15 years since 2001, NYHA class IV heart failure, IIB.&#x0D; The patient underwent surgical intervention: mitral valve replacement + W-shaped plastic surgery of the left atrium in combination with dosed resection of left atrium + tricuspid valve plasty with the imposition of a support ring + resection of the right atrium.&#x0D; Conclusion. Given the initial serious condition of the patient with advanced mitral restenosis, critically small left ventricular cavity, giant left atriomegaly of 169.4 × 115.8 mm (according to computed tomography) and high pulmonary hypertension (65 mm Hg), concomitant pathology of the right parts of the heart (tricuspid insufficiency and right atriomegaly), adequate tactics in mitral valve replacement and radical correction of the left atriomegaly lead to an improvement in the functional state of the heart as early as at the hospital stage.

Study on the Deformation Mechanisms of the Surrounding Rock and Its Supporting Technology for Large Section Whole Coal Cavern Groups

The control difficulty of whole coal cavern groups is greatly increased due to the characteristics of soft rock with low strength, large sections, and the mutual influence of crossed cavern groups. The large section gas storage cavern group is taken as the research background. In this paper, the equivalent circle method is used to solve the loose circle of a rectangular roadway, and numerical calculation is used to obtain the deformation and stress distribution laws of the surrounding rock under the excavation conditions of large section whole coal cavern groups (WCCG). The deformation and failure mechanisms of the surrounding rock are revealed under the linkage impact between large section whole coal cavern groups. The stratified reinforcement ring concept of “long cable-bolt-grouting” (LBG) was proposed for the stability control of surrounding rock in the WCCG. On the roof of whole coal cavern groups, the supporting configuration of a high-strength bolt with a high pre-tightening force and the high-strength anchor with a high pre-tightening force were determined. On the two sides and floor of the WCCG, the grouting scheme was determined. These two supporting configurations in both the roof and sidewalls were applied to the large section gas storage cavern group. The results show that the surrounding rock presents asymmetric deformation and failure characteristics due to the large excavation area and complex structure. Tensile failure and mixed tensile-shear failure mainly occur in the shallow part of the surrounding rock, while shear failure mainly occurs in the deep part of the surrounding rock. The roof displacement curves show a symmetric distribution and saddle distribution in the low- and high-negative pressure caverns, respectively. The maximum displacements are on the left and right sides of the cavern roof. The range of the loose rings is 3.34 m and 2.54 m, respectively, on the roof and the two ribs. The stratified reinforcement ring support technology of LBG can effectively reduce the failure depth of surrounding rock, and the surrounding rock is in a stable state. The study can provide a theoretical basis for the layout of large section cavern groups and the stability control of surrounding rock.

Comparative Outcomes of Mitral Valve Annuloplasty With Support Rings and Autopericardial Strip in Patients With Degenerative Diseases

Objective: To compare the outcomes of mitral valve annuloplasty with support rings and that of the current technique employing an autopericardial strip in patients with degenerative diseases (patent RU2774033C1, June 14, 2022).Materials and methods: The study included 105 patients with degenerative mitral valve disease who underwent surgery in our clinic from May 2010 to January 2020. Depending on the conduit type, the patients were divided into two groups. Group I included 53 patients who underwent mitral valve annuloplasty with an autopericardial strip. Group II included 52 patients who underwent annuloplasty with a support ring. Male patients predominated in both groups: 59.6% and 57.7%, respectively. The mean age of patients was 54.9 ± 9.5 years (36–78 years) in group I and 54.8 ± 10.05 years (32–70 years) in group II. In most cases, tri- and quadrangular resections of the P2 segment were performed, and in some cases, neochords were implanted to the A2 segment.Results: There was 1 death in group II as a result of progressive cardiovascular and multiple organ failure while in group I no hospital mortality was reported. At the discharge, 81.1% of patients in group I and 59.6% of patients in group II had no mitral regurgitation.Conclusions: The current technique of mitral valve annuloplasty with an autopericardial strip in patients with degenerative diseases allows for adequate stabilization of the annulus fibrosus and improves the surgical outcomes in selected patients. With our proposed method of mitral valve annuloplasty, the suitable strip length can be chosen for each patient.

Novel 3D Echocardiographic Technique for Mitral Calcium Mapping

Mitral annular calcification (MAC) is a common chronic degenerative process of the mitral valve fibrous support ring. MAC increases the risk of mitral valve dysfunction, all-cause and cardiovascular mortality, and worse outcomes in cardiac interventions. Echocardiography represents the first imaging modality for MAC assessment, but it has low specificity compared to cardiac CT in terms of distinguishing between calcium and dense collagen. Novel three-dimensional transesophageal maximal intensity projection (MIP) mapping allows for the real-time MAC distribution and depth visualization of the cardiac anatomy and represents a useful and promising tool for pre-procedural assessment and intra-procedural guidance of cardiac interventions.

Acoustic emission detection of micro-cracks under high pressure and high temperature in a deformation large-volume apparatus at the endstation P61B, PETRA III.

We successfully developed an in situ acoustic emission (AE) detection setup that allows recording of AE waveforms (triggered and streaming) and simultaneous x-ray diffraction and imaging on samples deformed at high pressure and high temperature (HPHT) conditions in the Aster-15 Large Volume Press at the synchrotron beamline station P61B. This high pressure AE detection system is a powerful tool to investigate AE phenomena from the HPHT chamber. Six commercial acoustic sensors, protected by a tungsten carbide support ring on each anvil of the same material, have excellent survivability throughout each successive experiment. By pulsing each sensor in succession, the average wave velocity through the anvils and cell assembly can be determined at any press load. The distance between the sensors is obtained by x-ray radiography and by logging the positions of each hydraulic ram. This provides a basis for accurately locating AE events in the sample. The feasibility of this AE detection setup was confirmed by compression and deformation test runs using several different self-designed AE sources in specialized assemblies. The present setup proves to be extremely efficient and accurate in measuring brittle processes in samples under HPHT. It is now available for applications for beam time and experiments without x rays at P61B. Combined with synchrotron x rays, in situ pressure, temperature, strain rate and stress, and phase changes can be monitored while recording AE activity. We provide a powerful tool to investigate the origin of earthquakes, for example, causing AE emissions due to brittle dehydration reactions or phase transformations in the Earth.

Rapid Morphological Measurement Method of Aortic Dissection Stent Based on Spatial Observation Point Set.

Post-operative stent morphology of aortic dissection patients is important for performing clinical diagnosis and prognostic assessment. However, stent morphologies still need to be manually measured, which is a process prone to errors, high time consumption and difficulty in exploiting inter-data associations. Herein, we propose a method based on the stepwise combination of basic, non-divisible data sets to quickly obtain morphological parameters with high accuracy. We performed the 3D reconstruction of 109 post-operative follow-up CT image data from 26 patients using mimics software. By extracting the spatial locations of the basic morphological observation points on the stent, we defined a basic and non-reducible set of observation points. Further, we implemented a fully automatic stent segmentation and an observation point extraction algorithm. We analyzed the stability and accuracy of the algorithms on a test set containing 8 cases and 408 points. Based on this dataset, we calculated three morphological parameters of different complexity for the different spatial structural features exhibited by the stent. Finally, we compared the two measurement schemes in four aspects: data variability, data stability, statistical process complexity and algorithmic error. The statistical results of the two methods on two low-complexity morphological parameters (spatial position of stent end and vascular stent end-slip volume) show good agreement (n = 26, P1, P2 < 0.001, r1 = 0.992, r2 = 0.988). The statistics of the proposed method for the morphological parameters of medium complexity (proximal support ring feature diameter and distal support ring feature diameter) avoid the errors caused by manual extraction, and the magnitude of this correction to the traditional method does not exceed 4 mm with an average correction of 1.38 mm. Meanwhile, our proposed automatic observation point extraction method has only 2.2% error rate on the test set, and the average spatial distance from the manually marked observation points is 0.73 mm. Thus, the proposed method is able to rapidly and accurately measure the stent circumferential deflection angle, which is highly complex and cannot be measured using traditional methods. The proposed method can significantly reduce the statistical observation time and information processing cost compared to the traditional morphological observation methods. Moreover, when new morphological parameters are required, one can quickly and accurately obtain the target parameters by new "combinatorial functions." Iterative modification of the data set itself is avoided.

A Systematic Approach for Energy-Efficient Design of Rolling Bearing Cages

Several aspects must be considered in the design of rolling bearing cages. One of the most important considerations relates to studying and developing a stationary approach for solving problems of heat and mass transfer during convection. In this context, this paper proposes, among other achievements, the development and validation of a model of heat generation that is used, as the basis for an energy-efficient cage design in the context of the roller bearings of axle boxes for rail transport. The forces of interaction of the cage with the bearing parts are determined. The energy-efficient design of the cage is performed with modified friction surfaces in the form of convex contours of the pockets and micro-hollows on the surfaces of the pockets and support rings. On the basis of a flat model, of the interaction between the cage and the bearing parts, the pressure forces on the driving and driven rolling elements in the zone of radial loading are determined. The frictional moment of the bearing has been determined based on the integral design of the cage without taking into account lubrication during the interaction of the cage with the jumpers and with the sides of the basing ring. The calculation of the temperature gradient with standard and improved designs of bearing cages has been performed while taking air blowing into account; results showed a decrease in the average level and growth rate of the bearings’ temperature gradient with an energy-efficient cage design. Based on the obtained results, and on the developed heat generation model, a systematic approach for energy-efficient design of rolling bearing cages is proposed. The proposed approach, as well as the respective developed models, were validated by obtaining and analyzing the experimental results.

Comparative analysis of mid-term outcomes of Rigid and NeoRing support rings in mitral regurgitation surgery: a prospective randomized trial

Highlights. For the first time, as part of a prospective randomized study, a comparative assessment of the mid-term results of mitral valve annuloplasty using a new biological NeoRing ring (CJSC NeoKor, Kemerovo) and a RIGID ring (CJSC NPP MedInzh, Penza) in patients with connective tissue dysplasia was carried out. Predictors of the conversion of sinus rhythm to atrial fibrillation and residual mitral insufficiency in the medium-term follow-up period were determined.Aim. To analysis and compare mid-term results of mitral valve annuloplasty conducted using NeoRing и RIGID rings.Methods. From November 2019 to March 2022, 62 patients with mitral valve (MV) dysplasia underwent MV annuloplasty using NeoRing semi-rigid rings (CJSC NeoKor, Kemerovo, n = 31) and rigid RIGID rings (CJSC NPP MedInzh, Penza, n = 31). There were no differences between the groups at baseline.Results. Two deaths were registered during inpatient treatment in the RIGID group. Both devices showed a satisfactory outcome during inpatient treatment in the form of restoration of MV function (p&lt;0.001) and the frequency of detected maximum residual mitral regurgitation (MR) up to grade 1 in the NeoRing group 9.7% and in the RIGID group 29%, respectively, no statistically significant intergroup differences were noted (p = 0.292). After 12 months, freedom from ≥2 grade MR in the NeoRing group was 93.5% and 77.4% in the RIGID group (p = 0.147). In the RIGID group, patients had higher values of the transvalvular mitral diastolic gradient – PAV 3.70 [3.00–4.40] mm Hg vs. NeoRing group 2.3 [2.05–2.85] mmHg (p&lt;0.001), as well as a higher transvalvular flow rate – VAV 79 [71–94] cm/sec vs. 70 [64–79] cm/sec (p = 0.017). The analysis of the achievement of composite primary endpoint (recurrence of ≥2 grade MR, MACCE, new onset arrhythmias, reoperations) by the device was carried out. The composite endpoint rate in the RIGID group was 3.067 times higher compared to the NeoRing group, odds differences were statistically significant (p = 0.037, 95% CI: 1.053–8.934).Conclusion. The outcome of MV annuloplasty conducted using rigid and semi-rigid rings revealed no significant differences in long-term survival and recurrence of MR between groups. Given the statistically significant difference in achieving the combined endpoint, lower inpatient and long-term indicators of transmitral pressure gradient, and a positive effect on cardiac chambers reverse remodeling, it was concluded that the use of semi-rigid NeoRing rings for MV annuloplasty when performing valvepreserving operations for connective tissue dysplasia is preferable.

Investigation of the Wear Resistance of a Journal Bearing with Polymer-Coated Grooved Support Ring

Introduction. In modern heavy-loaded friction units, metallopolymer coated bearings operating in the boundary friction mode are widely used. Their successful application is provided by the viscoelastic deformation of these coatings under load. To pass from boundary friction to liquid friction, it is required to create a bearing hydrodynamic wedge. Currently, the use of journal bearings with polymer-coated grooved support ring is hindered by the lack of a methodology for their calculation. This work analyzes a model of movement of a micropolar lubricant in the operating clearance of a journalbearing with a nonstandard support profile having a PTFE composite coating with a groove on the bearing surface. The study aims at establishing the dependence of the stable hydrodynamic regime on the width of the groove on the surface of the bearing profile. Materials and Methods. Tribological tests of journal bearings with a nonstandard bearing profile having a polymer coating with a groove on the surface were carried out on samples in the form of partial bushes (blocks). Using the equation of movement of a lubricant with micropolar rheological properties, as well as the continuity equation, new mathematical models were obtained that took into account the width of the groove, polymer coating, and nonstandard bearing profile. Results. A significant expansion of the applicability of design models of journal bearings with structural changes has been achieved. Polymer-coated bearings with a groove provided a hydrodynamic lubrication mode. The results obtained allowed us to evaluate the operational characteristics of the bearing: hydrodynamic pressure value, load capacity, and coefficient of friction. Discussion and Conclusions. The design of polymer coated journal bearing and a groove 3 mm wide on the surface of the liner provided a stable ascent of the shaft on the hydrodynamic wedge, which was validated experimentally. The experiments were carried out for journal bearings with a diameter of 40 mm with a groove 1–8 mm wide, at a sliding speed of 0.3–3 m/s and a load of 4.8–24 MPa.

Aerodynamic Damping of the Tubed Vortex Reducer in an Axial Compressor Disk Cavity

The tubed vortex reducer in the axial compressor can destroy the vortex in the disk cavity, by a thin-walled tube, to reduce the total pressure loss. The tube may suffer from vibration problems, such as flutter and forced vibration, which are closely related to aerodynamic damping. In this paper, the energy method and the influence coefficient method are used to study the aerodynamic damping of the tube. Based on the modal characteristics, steady and unsteady flow characteristics of the tube, the first and second modes with lower frequencies and greater vibration risk are selected as the analysis objects. The energy method is used to calculate the aerodynamic damping of the tube with different amplitudes, which shows that the results approximately meet the linear assumption and are accurate. The results obtained by the influence coefficient method show that the aerodynamic influence between adjacent tubes is very small, and the effect of inter-tube phase angle on the aerodynamic damping can be ignored. Finally, it is found that the effect of structural coupling caused by the support ring on the aerodynamic damping of the tube is mainly reflected in two aspects: frequency reduction and tube mode coupling.

Study of the Wear Resistance of a Friction unit with a Non-Standard Support Profile and a Metal Coating

The theoretical calculations and the results of experiment for a friction unit consisting of a wedge-shaped support surface are presented in this research paper. The slider on the tread surface has a metal alloy. The lubricating fluid is represented by a lubricant with non-Newtonian characteristics; it has the laminar flow in this unit. The friction unit functions when the cavity between the slider and the support ring is completely filled. To solve the theoretical problem under given conditions, the equations of continuity, the rate of mechanical energy dissipation, the values of the expression for the displacement of a non-Newtonian fluid were used. In addition, equations were used to characterize the profile of a slider with a melt on the tread surface. The presented problem was solved by the self-similar variable method with asymptotic expansion in the smallest parameter. Upon calculation, it is given the equations for the first and zero pressure approximations and it is determined the velocity field are determined with and without the molten metal. Further, the friction force and load capacity were found using the non-Newtonian properties of the lubricating fluid and the above structural characteristics of non-standard surfaces for friction contact.

Dynamic Characteristics Analysis of Rotor System with Fitting Tightness of Elastic Ring Support Structure

Dynamic Characteristics Analysis of Rotor System with Fitting Tightness of Elastic Ring Support Structure

Design optimization of the suspension unit of the liner in the combustion chamber housing

The design of the suspension unit of the flame tube in the housing of the annular combustion chamber of a ground-based gas turbine installation of a gas pumping unit is given for placing it in a device for fixing the flame tube in the combustion chamber housing, where automatic clearance selection is required arising between the contacting surfaces of the docking nodes of the combustion chamber and the nozzle apparatus of the turbine, when the combustion chamber is operating as part of the engine. The proposed design of the suspension unit of the flame tube in the annular combustion chamber housing makes it possible to increase the reliability and resource of the combustion chamber and, in general, the entire ground-based gas turbine installation by eliminating the jamming of the split rings in the cups of the suspension units and the misalignment of the pushers relative to the suspension units and split support rings.

Universal reposition and fixation ring for surgical treatment of acetabulum fractures: preliminary results of laboratory static tests

BACKGROUND: Several structures are widely used in the surgical treatment of long-standing fractures of the BB, such as support rings of M. Muller, BurchSchneider, rings of PROTEK (Switzerland) implanted in the BB. In traumatology practice, rings are used to strengthen fractured walls. However, these rings are not functionally designed for open reposition and fixation of columns and fractures, followed by TBS endoprosthetics with cement fixation of the components of the endoprosthesis. Recently, primary endoprosthetics of EP TBS became the trend for displaced fractures of the BB, which is considered the best option for surgical treatment of BB fractures. In the literature, no analogs of our ring were available, which provides CHP in the treatment of BB fractures.&#x0D; AIM: To study the deformation properties of a repositional fixation ring with an outer diameter of 52 mm with a stiffening rib.&#x0D; MATERIALS AND METHODS: A ring has been developed for the surgical treatment of acetabulum fractures (Patent for Invention No. 2692526 dated 26.06.2019 under Application No. 2018133671 dated 25.09.2018.; Bul. No. 18 dated 26.06.2019). For mechanical testing, a ring with an outer diameter of 52 mm with a stiffening rib was manufactured by sequential sintering using additive technologies by Konmet LLC (Moscow). Laboratory mechanical tests were conducted by the Testing Laboratory of Medical Devices and Materials of the FSBI NMIC TO named after N.N. Priorov (Moscow).&#x0D; RESULTS: A static testing of a ring with a stiffener for compression, stretching, torsion, joint stretching, and twisting of the edges of the ring connector was performed, and its deformation properties and reaction to external loads during static tests were examined. The load corresponded to the deformation of 2 mm, kN; compression, 0.209; tension, 0.082; torsion (angle of rotation of 5 degrees, Nm), 9.422; and joint stretching with twisting of the edges of the ring connector (load corresponding to the deformation of 10 mm, kN), 0.060.&#x0D; CONCLUSION: The results of the initial study of the deformation behaviors of the new ring design clearly show the elastic nature and deformation properties of the ring, which were attributed to the stiffening rib. The positive primary results of studying the deformation behaviors of the ring reinforced with a stiffening rib indicate the possibility for clinical trials and the direction of further refinement of the design..

Case of Dilated Cardiomyopathy in Combination with Left Atrial Myxoma and Left Atriomegaly (Rare Clinical Case)

Case description. A 41-year-old male patient F. was admitted to the Department ofSurgical Treatment of Ac-quired Heart Diseases of the National Amosov Institute of Cardiovascular Surgery of the National Academy of Medical Sciences of Ukraine with a diagnosis: Dilated cardiomyopathy. Mitral-tricuspid insufϐiciency. Left atrial myxoma. Left atriomegaly. Pulmonary hypertension. The patient was operated with heart failure symptoms of NYHA functional class IV.&#x0D; After a week of medical preparation and additional examination,the patient was successfully operated on (remov-al of the left atrial myxoma, imposition of support rings on the left and right atrioventricular openings, paraanular plicacy of the left atrium). The postoperative period proceededwithout signiϐicant complications. On the 12th day after the operation, the patient was discharged in satisfactorycondition. In the remote period the patient died suddenly 3 years later.&#x0D; Conclusion. Taking into account the initial serious condition of a patient with advanced heart disease with a reduced left ventricular ejection fraction, left atriomegaly (7.8 cm), pulmonary hypertension (50 mm Hg) and comorbidities, complex reconstruction of the left heart in atriomegaly and ventriculomegaly leads to an improvement in the functional state of the myocardium and morphometric indicators of left atrium and left ventricular ejection fraction.